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US 6,606,446 B1Granted
Miniature variable attenuator
AssigneeJDS Uniphase Corporation
InventorsRonggui Shen, Jingyu Xu, Jing-Jong Pan
Life of this patent
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Abstract
An improved optic attenuator controllably filters an optical signal after the signal has been expanded and collimated. The optical signals are preferably expanded and refocused by a single GRIN lens, the signal passing through a variable filter between the GRIN lens and a reflector, and again between the reflector and the GRIN lens. Both the input and output fibers can be held within a single sleeve in alignment with the GRIN lens. The amount of attenuation can be indicated by a potentiometer.
Claims12
A variable attenuator comprising:
- an electrical component having a body that defines a path and an element which is movable along the path to vary an electrical characteristic of the component;
- an input optical fiber;
- an output optical fiber disposed in an optical path of an optical signal from the input fiber;
- an optical filter having a filter density which varies between a lower density region and a higher density region, the filter coupled to the component so that an effective region of the filter is disposed in the optical path between the input fiber and the output fiber, the element of the component moving along the path when the effective filter region moves between the low density region and the high density region so that the electrical characteristic of the component indicates effective filter density.
1 more element
A variable attenuator comprising:
- a sleeve having a first end and a second end;
- an input optical fiber disposed within the sleeve and having an end adjacent to the second end of the sleeve;
- an output optical fiber disposed within the sleeve and having an end adjacent to the second end of the sleeve;
- a GRIN lens adjacent the second end of the sleeve, the GRIN lens having a length of approximately a quarter pitch and aligned to expand an optical signal from the input fiber;
- a reflector disposed in the optical path of the optical signal from the GRIN lens, the reflector aligned to direct the signal back through the GRIN lens and into the output fiber;
- an optical filter disposed in the expanded optical path between the GRIN lens and the reflector, the filter having a filter density which varies between a lower density region and a higher density region;
- and
- an electrical component coupled to the filter for moving the filter within the expanded optical path such that the optical signal is variably attenuated.
5 more elements
A variable attenuator comprising:
- a potentiometer having a body that defines a path, a wiper, a rotatable screw coupling the wiper to the body to translate the wiper along the path when the screw rotates relative to the body;
- a sleeve to hold an input optical fiber and an output optical fiber relative to a housing;
- a GRIN lens disposed in an optical path of an optical signal from the input fiber;
- a reflector disposed in the optical path from the GRIN lens, the reflector aligned to direct the signal back through the GRIN lens and into the output fiber;
- an optical filter having an effective filter region disposed in the optical path between the GRIN lens and the reflector, the filter having a filter density which increases from a lower density region to a higher density region, the filter coupled to the potentiometer so that the effective region moves between the low density region and the high density region when the screw rotates;
- and
- a circuit coupled to the potentiometer to sense an electrical signal which indicates a position of the wiper along the path, whereby effective attenuation of the attenuator is also indicated.
4 more elements
Dependencies are inferred from the claim text.